The field of the present invention is building construction hardware for mounting components such as utilities.
Building construction frequently uses steel web joists. Such devices employ two beams. The beams are mutually parallel and spaced apart to create a large moment of inertia for the joist. Cord elements extend at angles between the two so the beams will act as one in bending. Each beam includes a set of two elongate angle elements which are also mutually parallel. The cord elements extend for anchoring to between the elongate angle elements which form a cord space to receive the elements. Each angle element includes two legs extending at a right angle to one another, a first leg which is parallel with the first leg of the other angle element to define the cord space and a second leg extending in the opposite direction from the second leg of the other angle element to generally define a plane. The two first legs extend to define parallel edges at the distal ends of two parallel webs.
Seismic adapters have been associated with such steel web joists through the set screw clamping of brackets to one web of the upper beam of a steel web joist. In this regard, reference is made to U.S. Pat. No. 6,098,942, the disclosure of which is incorporated herein by reference.
Other such seismic adapters now have been associated with such steel web joists by positioning two flat washers about one of the sets of angle elements. One washer lies in the plane of the second legs such that it extends across the cord space in juxtaposition with the second legs. A second washer is arranged to abut against the parallel edges of the first legs, also extending across the cord space. A threaded stud extends between the washers with a nut or bolt head retaining the first washer in juxtaposition with the second legs. The threaded stud extends beyond the second washer to accommodate attachment hardware. The entire assembly is then clamped to the joist by threading a nut up snug against the attachment hardware and, in turn, the second washer. Where access to the top surface of the steel web joist is unavailable, set screw clamps associated with a depending web of the upper beam of the joist may be employed. There are industry requirements that such attachments be within six inches of the attachment point of a cord element with the upper beam. The cord elements typically extend at angles to the upper beam. These elements can interfere with the depending structure of the aforementioned prior devices to limit placement along the joist beam.
The present invention is directed to a seismic adapter for attachment to the web of an upper beam of a steel web joist. The adapter includes two anchor plates joined together along an edge of each. Clamps oriented to receive the web are arranged at the opposite ends of these plates. A mounting plate is fixed to the anchor plates as well to receive a threaded attachment.
In a first separate aspect of the present invention, the anchor plates are joined together to form an angle substantially less than 180xc2x0. The angle provides a close fit adjacent a cord element extending at an angle other than 90xc2x0 from the upper beam of the joist.
In a second separate aspect of the present invention, each clamp includes an anvil extending from the end of each anchor plate. A threaded hole is aligned with the anvil and receives a threaded shaft extendible to the anvil. The anvil may have a concave seat and the threaded shaft a convex end which can operate on thin webs to deform the web for greater purchase by the clamp.
In a third separate aspect of the present invention, the mounting plate is fixed to the anchor plates. Increased structural rigidity is established through this attachment of the mounting plate.
In a fourth separate aspect of the present invention, the foregoing separate aspects are contemplated to be employed in combination.
Accordingly, it is an object of the present invention to provide an improved seismic adapter. Other and further objects and advantages will appear hereinafter.